None
Not applicable.
The present invention relates generally to product identification and more particularly to laser bar coding of products, such as biopsy cassettes.
There is an identified need for an identifying mark (e.g., bar code) on cassettes commonly used in biopsies (histology). Marking to identify the source of the tissue sample borne by the cassette historically has been done manually with a marking pen or by thermal transfer foil/articulated heat scribed (Triangle Biomedical Services, Durham, N.C.). Neither the manual pen nor the scribe can mark accurate bar codes.
Conceptually, a laser may mark the cassette. Unfortunately, direct laser marking (to an acceptable black) of the typical unmodified cassette material (e.g., DELRIN(copyright) brand of a linear polyoxymethylene-type acetal resin, E.I. du Pont de Nemours and Company, Wilmington, Del.) requires a short wavelength laser (e.g., NdYAG laser @ 1.06xcexc wavelength), which is far more expensive than an equal powered CO2 laser (@ 10.6xcexc wavelength) and beyond the financial resources of the typical histology laboratory. Conceivably, the cassette material might be modified in such a way as to enhance direct laser marking contrast (see, for example, U.S. Pat. No. 5,977,514) when using a lower cost CO2 laser, but this may affect its molding and chemical survival characteristics and would significantly increase the cost of each cassette.
As tissue sample traceability and automation become increasingly important, there is a need for economically and reliably creating bar codes on low cost cassettes, e.g., which cassettes can be marked by low cost (CO2 laser) markers without requiring markability enhancing additives.